Sound Speed and Attenuation in Multiphase Media.

摘要

One research goal developed from conducted shallow water (SW) acoustic transmission experiments in sandy-silty areas [1] revealed a nonlinear power law frequency-dependent attenuation at lower frequencies consistent with results reviewed in [2,3] and the observations by the ONR-HEP program. The Biot Theory [4] predicts that sandy sediment attenuation should have a quadratic dependence, however the nonlinear dependence observed was closer to a 1.8 power law most likely due to modal effects. Thus one long-range goal is to develop a simplified theory of sediment attenuation [5] verified by measurements that can be applied to ocean sediments. A second long-range goal is to better understand that acoustical behavior of individual bubbles and bubbly assemblages in water and water-filled sediments. The focus is on attenuation, dispersion, and bubble response near and about the resonance frequency.